CVE-2026-77607 — mediawiki/semantic-media-…
MEDIUMCVE-2026-77607 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in mediawiki/semantic-media-wiki. A fix is available for mediawiki/semantic-media-wiki — see the affected versions and patch details below.
Semantic MediaWiki affected by Special:Ask table `sep` parameter reflected XSS
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-77607.
Real-World Exposure
mediawiki/semantic-media-wikiReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Failure mode
sep was inserted verbatim into the HTML that joins a table cell's values. This made it possible to inject HTML through the separator value. The same unsanitised table HTML is produced both for the standard Special:Ask render and for its raw request output (request_type=raw), so the injection was reachable without authentication.
Remediation
- In all non-wiki output modes (HTML, raw request, file),
sepis escaped unless it is a safe<br>variant. - This preserves legitimate line-break separators while blocking markup injection.
Maintenance note
If the table renderer ever gains richer separator semantics, keep the whitelist explicit. Do not expand the allowed HTML surface casually.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | mediawiki/semantic-media-wiki | all versions | 7.2.0composer require mediawiki/semantic-media-wiki:^7.2.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for mediawiki/semantic-media-wiki, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update mediawiki/semantic-media-wiki to 7.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-77607 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-77607 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-77607. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-77607 in your dependencies?
O3 Security finds CVE-2026-77607 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.